Rename doc file for DAN Marketplace Bid Adapter into danmarket.md (#631)

* Add doc for DAN_Marketplace Adapter

* Fix format of DAN Marketplace doc file

* Fix DAN Marketplace doc

* Rename doc file for DAN Marketplace Bid Adapter into danmarket.md

dev-docs/bidders/danmarketplace.md → dev-docs/bidders/danmarket.md

@@ -5,8 +5,8 @@ description: Dentsu Aegis Network Marketplace Bidder Adapter
 top_nav_section: dev_docs
 nav_section: reference
 hide: true
-biddercode: danmarketplace
-biddercode_longer_than_12: true
+biddercode: danmarket
+biddercode_longer_than_12: false
 prebid_1_0_supported : true
 ---